The Rubber Pavements Association

Transcription

1 The Rubber Pavements Association Texas DOT Asphalt-Rubber Workshop January 17, 2012 Mark Belshe Executive Director

2 Dedicated to encouraging greater usage of high quality, cost effective asphalt pavements containing recycled tire rubber.

3 What is the RPA? The RPA is a non-profit industry association comprised of: Crumb Rubber Producers Contractors Who Use Crumb Rubber in Pavements Equipment Manufacturers Consulting Firms Testing Laboratories

4 Where are the RPA members? Australia, Austria, Canada, Germany, Italy, Mexico, Netherlands, Portugal, Saudi Arabia, South Africa, South Korea, Sweden, United Kingdom, and United States

5 TECHNOLOGY TRANSFER THROUGH Seminars Field Tours Sponsoring Research RPA Newsletters Publishing Reports Reference Library Monitoring Tire Laws Provide Guidance for Agencies in Use of CRM Asphalt

6 Who advises the RPA? The RPA Technical Advisory Board is made up of the nation s leading experts on crumb rubber and rubber modified asphalt pavements. George Way - Chairman Retired Arizona DOT Dr. Kamil Kaloush Vice Chairman Arizona State University

7 Technical Advisory Board cont. Richard Stubstad, Applied Research Associates Ali Zareh, Arizona DOT Jack Van Kirk, Basic Resources Inc. Joe Cano, Bureau of Indian Affairs Serji Amirkhanian, Clemson University (Retired) Jorge Sousa, Consulpav Dr. H. Barry Takallou, CRM Byron Lord, Dep. Director, Office of Pavement Technology, FHWA

8 Technical Advisory Board cont. Anne Stonex, MACTEC Engineering & Consulting Maghsoud Tahmoressi, PaveTex Engineering and Testing, Inc. Larry Smith, Florida DOT Materials Engineer (retired) Douglas A. Bernard, Quixote Transportation Safety Mark Belshe, Rubber Pavements Association Shakir Shatnawi, Caltrans (retired) John Epps, Texas A&M University Larry Smith, Florida DOT Materials Engineer (retired) K.C. Evans, Texas DOT

9 Technical Advisory Board cont. Dale Rand, Texas DOT Rudy Jimenez, University of Arizona Peter Sebaaly, University of Nevada Reno Hussain Bahia, University of Wisconsin

10 Does RPA recommend the use of all paving material containing crumb rubber from scrap tires? RPA has strict criteria for paving materials and processes the association recommends or promotes Non-patented, non-proprietary processes

11 Paving materials must be proven through the following: Extensive laboratory research Construction evaluation research Successful field performance in all climates

12 What products currently meet the RPA criteria? Asphalt-Rubber as defined by ASTM D8 Asphalt-Rubber is a blend of asphalt cement, reclaimed tire rubber and certain additives, in which the rubber component is at least 15% by weight of the total blend and has reacted in the hot asphalt cement sufficiently to cause swelling of the rubber particles.

13 RPA sponsored Research Oregon State University - PI R. G. Hicks Ph.D. Life Cycle Cost Analysis of A-R Paving Materials. Quality Control Manual for A-R Binders. Rubber Modified Binder Specification Evaluation (Caltrans).

14 More RPA Projects Mechanistic Overlay Design Method for Hot Mix. Influence of Aging on Fatigue Behavior. A-R Design and Construction Guidelines. Project Reviews for AZ, CA, and TX FHWA Recap of CRM Summary of Practices

15 Standards & Specifications Development ASTM Standard Guide for OGFC, A-R Bituminous Surface Treatments Performance Based Specifications for Asphalt Rubber Binder & Mixes Asphalt-Rubber Chip Seals

16 Aged Project Performance Evaluations Arizona California Texas

17 Why Do We Modify Asphalt? Unmodified asphalt can be sensitive to temperature variations Brittle in cold temperatures Thermal Cracks Softens in high temperatures Rutting and surface deformations Modification makes asphalt more temperature stable

18 Ways to Modify Asphalt Air Blowing Flux Oils PPA - Polyphosphoric acid SBR Latex SBS Styrene Butadiene Styrene Very common usage Shortage of polymers in 2008 Crumb Rubber derived from Scrap Tires

19 Why Put Rubber In Asphalt? The purpose is not to get rid of tires but to enhance the performance of the binder and mix. Tires have great engineering properties, they don t crack in the cold or melt in the heat. They have a wider range of performance temperatures than asphalt. Make asphalt pavements that perform like tires.

20 Why Put Rubber In Asphalt? Tire rubber is an engineering tool to: Reduce cracking Increase asphalt content and asphalt film thickness Prevent bleeding, flushing, and drain-down An aid to increase performance life Save Money in reduced maintenance Save money in project cost through reduced thickness Increase safety and reduce noise

21 Rubberized Asphalt, Rubber Modified Asphalt, and Asphalt-Rubber Methods of Combining Components Wet Process Rubber is added to liquid asphalt before mixing at the hot plant, rubber is wet before mixing with aggregates. Dry Process- Rubber is added at the same time the asphalt and aggregate are mixed, rubber is dry before mixing with the aggregate and liquid asphalt.

22 Adding Rubber to Asphalt Wet Process - with agitation Adding graded rubber to asphalt and mixing and reacting-requires agitation due to size and large amount of rubber used. Wet Process no agitation Adding fine rubber typically < #30 to asphalt at the terminal-generally little or no agitation. Often referred to as terminal blend. Dry Process Use CRM as substitute for 1-3% of Aggregate by mixing crumb rubber directly with aggregate

23 Wet Process-with Agitation Method of modifying asphalt cement with CRM and other components Most widely used in California and Arizona, Texas. Also used in Florida, Nevada, Nebraska, New Jersey, Massachusetts, Canada. Contains % crumb rubber agency spec vary Particle size ranges from # 8 to #10 top size

24 Wet Process-No Agitation Contains from <5%-18 % crumb rubber Particle size ranges from 40 to 80 mesh top size Can also contain polymers Used in Arizona,California, Florida, Texas, and several northeastern states Often referred to as Terminal Blend

25 Asphalt Rubber vs Terminal Blend Advantages Open technology Use of high binder contents Excellent Ageing Demonstrated ability to resist reflective cracking Long documented history of performance Cost effective from life cycle perspective Uses lots of crumb rubber Advantages Performs better than neat asphalt Easy to use Uses crumb rubber but less than asphalt rubber Can be performance graded Does not require special equipment in field.

26 Asphalt Rubber History Developed in 1960 s by City of Phoenix Engineer Referred to as the wet process or McDonald Process Large amount of crumb rubber used as a Binder Modifier Needs constant agitation ASTM definition 15% rubber minimum

27 Asphalt Rubber 80 % Asphalt 20 % Ground Tire Rubber

28 PRODUCTS AND PROCESSES IN THE PUBLIC DOMAIN

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30 Every Mile of Asphalt Rubber Road Recycles 4000 Waste Tires

31 In the last ten years, RPA Members have recycled enough tires to make a scrap tire pipeline from Prudhoe Bay, Alaska to Washington, D.C.!

32 Questions? For more information call (480)